A U-shaped wooden staircase is a type of staircase that features a curved design, with one or more turns. In this case, the staircase is made of oak, a hardwood known for its durability and resistance to wear and tear. The newel posts, handrail, and threads are all made of oak as well, which gives the staircase a cohesive and polished look. The risers, which are the vertical boards that close the space between the treads, are made of red deal, a type of wood that is known for its strength and durability. The string, which is the horizontal board that runs along the back of the risers, is also made of red deal. The spindles, which are the vertical posts that support the handrail, are made of poplar, a type of wood that is known for its lightweight and relatively straight grain. This U-shaped wooden staircase with oak newel posts, oak handrail, oak threads, red deal closed risers, red deal cut string and poplar spindles is a beautiful and sturdy addition to any home.